Safety device for engine cranking



July 8, 1924'. 1,500,781

F. E. TURNER SAFETY DEVICE FOR ENGINE CRANKING Filed Jan. 29 1923INVENTOR. Francis E. Turner ATTORNEY Patented July 8, 1924.

FRANCIS E. TURNER, F CRESCENT CITY, CALIFORNIA.

SAFETY DEVICE FOR ENGINE CRANKING.

Application filed January 29, 1923.

,To all whom it may concern:

and useful Improvements in Safety Devices for Engine Oranking; and I dodeclare the following to be a full, clear, and enact description of thesame, reference belng had to the accompanying drawings, and to thecharacters of reference marked thereon, which form a part of thisapplication.

This invention relates to improvements in safety devices for use inconnection with the cranking of-gas engines by hand, an opera- .tionwhich must still be done with the engines of most automobiles of acertain popular make.

The principal object of my invention isto. provide a means forpreventing a reverse rotation from the normal of the crankshaft of theengine, due to what is commonly known as backfiring, from being impartedto the cranking handle, which is of course in operative connection withthe crankshaft duringthe cranking operation.

Such a sudden reversal of movement as takes place with a backfire, iftransmitted to the cranking handle, is very often the cause of brokenarms and other accidents, and the purpose of my device is to eliminate.suc unfortunate occurrences. v V

Another object of my invention is to provide a device for the purposewhich may be very easily applied to the car, with only the alteration ofa singleoriginal part or its replacement by another made especially,being necessary.

A further object of the invention is to producea simple and inexpensivedevice and yet one which will be exceedingly eflective for the purposesfor which it is designed.

These objects I accomplish by means of such structure and relativearrangement of parts as will fully appear by a perusal of.

the following specification and claims.

In the drawings similar characters of ref erence indicate correspondingparts in the several views.

I Fig. 1 is a fragmentary outline of the front of an automobile, showingmy .improved safety device installed thereon.

Fig. 2 is an enlarged sectional elevation of the device and crankingapparatus, detached and showing the same in the normal crankingposition.

tate

Serial .No. 615,560.

F 3 is a similar view, showingthe-posie tioning of the partsaftera-Tkickback of theshaft has taken place.

Referring now more particularlyto the characters of reference onthedrawings, the

numeral 1 denotes the usual transverse spring supportmg member ofthelcar, which supports the front spring 2,, U-clips 3 being employed tobind the spring and support together, the clipsalso securing a bearingmember. l'in which the cranking shaft ,5; is slidably andturnablyjournaled.

This shaft as usual, carries onits inner end a notched member 6 adaptedto 'be placed into detachable engagement with a transverse pin 7 on theouter end of the engine crank shaft 8.

Theouter end of theshaft is threaded righthand for a certain distance asshown at 9, and threaded onto this portion is a ratchet wheel 10 engagedby ,a pawl 11 pivoted on a plate 12 mounted inconnection with the member4 and one of the clips 3, the ratchets and pawl beingso disposed thatthe wheel may turn freely a clockwise direction but is held fromrotation in the opposite direction.

The usual spring 13 is placed about the shaft between the members land10, and acts to move the shaft 5 away from the shaft 8.

Placed snugly on said shaft 5 outwardly of the member 10 is a thinnarrow ring 14 and outwardly of the ring the upper end 15 of thecranking-handle member 17 is threaded on to the shaft. 7

A retaining nut 17 is screwed on to the outer end of said shaft 5, beingheld against movement by any suitable means, this nut acting to preventremoval of the handle member.

In the operative positions of the parts the handle member 15 is snugagainst the outer nut 17, the ring 14.. is snug-against the oppositeface of the handle member, while the ratchet wheel 10 is snug againstthe opposite face of the ring, leaving a certain number of the threads 9unoccupied beyond the wheel 10, or towardthe bearing l.

If then the handle is rotated inthe customary clockwise orright handdirection,

its tendency is to move along the shaft, following the threads. This,however, it cannot do owing to the member 10 in its path of movement,this member, besides being a ratchet wheel, is in efiect a lock or stopnut, keeping the handle member in said members,

definitely apart, and yet has such a small bearing surface that anytendency of the *would not of course turn.

This undesired result is preventedby the interposition of the narrowring 14 between which holds the two nut 10 to turn on'the shaft iseliminated,

and it then performs its function as a stop to prevent similar movementof the handle member. The result therefore, is that the shaft 5 isturned, and the member 10 turns with it without moving along said shaft,the pawl 11 offering no resistance to move- .ment of the wheel 10 inthat direction.

' If however the shaft 5 kicks back, the

member 10 is immediately prevented from turning back with the shaft byreason of the pawl 11, the result being that the member 10 is caused tomove along the shaft in the i only direction which the cut of thethreads 9 will permit, which is away from the ring 1 1 and handleportion 15. 'i

This of course effectively breaks the seal or flOCk' between the abovenamed three members, leaving the handle member, which is still graspedby the hand of the operator and thus resists being turned backwards,free to also move along the shaft with the tendency to so move impartedthereto by the backward rotation of the shaft, instead of its turningwith the shaft and possibly breaking the arm of the operator.

After such a back-kick, the members 10 and 1.5 should be retracted tothe original positions as described hereinbefore, before again startingcranking operations.

From the foregoing description it will be readily seen that I haveproduced such a -device as substantially fulfills the objects of theinvention as set forth herein.

l/Vlnle thls specificat on sets forth indetail the present and preferredcol'lstruction of the' device, still in practice such deviationsfromsuch detail may be resorted to as do not form a departure from thespirit of the invention, as defined by the appended claims.

Having thus described my invention, what I claim as new and useful anddesire to cure by Letters Patent is:

1. A safety cranking device for gas engines comprising ashaft adapted tobe operatively connected to thecrank shaft of 'tation thereof, a

the engine, the outer end of said shaft being threaded in the directionof normal rocrank-handle member threaded on to said shaft, a stop memberthreaded on to the shaft inwardly of the handle member, said stop memberbeins. normally positioned to prevent movement of the handle memberalong the shaft in that direction, and means preventing rotation of thestop member with the shaft other than in the direction of normalrotation of the latter, whereby when a reverse-direction movement isimparted to the shaft the stop will be automatically caused to movealong the shaft and away from the handle member.

2. A safety cranking device for gas engines comprising a shaft adaptedto be operatively connected to the crankshaft of the engine, theouterend of said shaft being threaded in the direction of normalrotation thereof, a crank-handle member threaded on to said shaft, astop member threaded on to the shaft inwardly of the handle member, andfree to rotate with the shaft only in the direction of normal rotationof the latter, and means on the shaft between the handle and stop memberfor preventing longitudinal movement" of the handle member on the shaftand for pre- 7 venting the turning of the two together 011 the shaft;

3. A safety cranking device for gas engines comprising a shaft adaptedto be operatively connected to the crankshaft of the engine, the outerend of said shaft being threaded in the direction of normal rotationthereof, a crank-handle member thread ed onto'said shaft, a stop memberthreaded on to the shaft inwardly of the handle member, and free torotate with the shaft only in the direction of normal rotation ofthelattcr, and a spacer ring having relatively small bearing area fittedon the shaft between the stop and handle members.

f. A safety cranking device for gas engines having a shaft adapted to beoperatively engaged with the crank-shaft of the engine, comprising ahandle member threaded onto said shaft, the threads running in thedirection of normal rotation of the/shaft, a stop member threaded ontothe shaft inwar lly of the handle member, ratchetteeth cut in theperiphery of said stop member, a fixed pawl engaging the same, and aspacer ring having relatively small bearing area fitted on the shaftbetween the stop and handle members.

In testimony whereof I affix my signature.

FRANCIS E. TURNER.

